Question

What is the solution to the equation? square root -2x-5-4=x A. -7 and -3 B. 3 and 7 C. -3 D. 7

Answer 1

Answer:

3

Step-by-step explanation:

step1 Isolate the square root on the left hand side

    Original equation

    √2x-5-4 = -x

    Isolate

    √2x-5 = 4-x

step2 eliminate the radical on the left hand side

    Raise both sides to the second power

    (√2x-5)2 = (4-x)2

    After squaring

    2x-5 = x2-8x+16

step3 Solve the quadratic equation

    Rearranged equation

    x2  - 10x  + 21 = 0

    This equation has two rational roots:

      {x1, x2}={7, 3}

step4 Check that the first solution is correct

    Original equation, root isolated

    √2x-5 = 4-x

    Plug in 7 for  x  

     √2•(7)-5 = 4-(7)

     Simplify

     √9 = -3

     Solution does not check

     3 ≠ -3

step5 Check that the second solution is correct

    Original equation, root isolated

    √2x-5 = 4-x

    Plug in 3 for  x  

     √2•(3)-5 = 4-(3)

     Simplify

     √1 = 1

     Solution checks !!

    Solution is:

     x = 3